F31 335d, what’s caused this?

[gareth h]

I got a drivetrain fault which put the car in limp mode, when I checked the fault codes they suggested incorrect air measurement at MAF / oxygen sensor.
Pulled the engine cover off to clean the MAF and was confronted with this, looks like it has melted, of there’s been a small explosion!
Any thoughts?

[numtumfutunch]

Havent got a scooby however there is a fantastic forum over here:

https://f30.bimmerpost.com/forums/forumdisplay.php...

[ridds]

Hot EGR return caused a weak spot in the plastic part. Then blew out with pressure I would say.

[gareth h]

ridds said:

Hot EGR return caused a weak spot in the plastic part. Then blew out with pressure I would say.

Thanks, it had a recall for EGR a few weeks ago, just done some research, seems I’m quite lucky there have been a lot of catastrophic fires!

[helix402]

Air mass meters are self cleaning. They are sometimes damaged by attempts to clean them. Glad you found the problem.

[ian332isport]

ridds said:

Hot EGR return caused a weak spot in the plastic part. Then blew out with pressure I would say.

Agreed. I bet the EGR return pipe is directly opposite that hole.

[E-bmw]

ian332isport said:

ridds said:

Hot EGR return caused a weak spot in the plastic part. Then blew out with pressure I would say.

Agreed. I bet the EGR return pipe is directly opposite that hole.

In that case, the hole is exactly where the hot gases will be directed from the EGR.

[rottenegg]

Doesn't sound like the EGR 'cooler' is doing it's job then.

[gareth h]

It’s back with Sytner at Swansea, hoping they treat it as a warranty job (I think they will)

[ridds]

Ironically, you can see the EGR temperature probe just at the bottom left of the red circle in the image.

You'd think it would have detected the error state.

[gareth h]

ridds said:

Ironically, you can see the EGR temperature probe just at the bottom left of the red circle in the image.

You'd think it would have detected the error state.

I was surprised that there wasn’t a high inlet temp fault, I mean how hot does it have to be to melt ABS?

[gareth h]

Ok, just an update, car back from Sytner, new inlet manifold and presumably egr cooling circuit (for the third time!), I’m seriously thinking about a egr delete.
I’m a bit disturbed that inlet temps can get to plastic melting temp without a fault code, would anybody know if inlet temperatures can be read live from the obd?

[Sim89]

You can blank off the EGR physically and leave all of the hardware in place.

Blanking kit
http://dgmaps.co.uk/shop/n47-n57-egr-blank-kit/

The key is thing is to have the EGR mapped out of the DME, as it is linked to DPF regeneration. Often people will blank the EGR without doing this, causing DPF problems in the future.

I've had mine (N57, 330d) blanked and mapped out for 70k now, without issue and plenty of life left in the DPF.

[gareth h]

Sim89 said:

You can blank off the EGR physically and leave all of the hardware in place.

Blanking kit
http://dgmaps.co.uk/shop/n47-n57-egr-blank-kit/

The key is thing is to have the EGR mapped out of the DME, as it is linked to DPF regeneration. Often people will blank the EGR without doing this, causing DPF problems in the future.

I've had mine (N57, 330d) blanked and mapped out for 70k now, without issue and plenty of life left in the DPF.

Thanks, that looks like a straightforward solution